This invention relates to a coupler device for joining two tunnel lining segments together.
Previous inventions disclose devices, which align and restrain two tunnel lining segments of a ring. However they are limited by the accuracy of their manufacture or the accuracy of the casting of the tunnel lining segment. In all cases the joining device is inserted prior to the segments being pushed together by rams and relies on geometric interference to provide restraint.
According to the present invention there is provided a coupler device for joining together two construction segments of a construction member selected from the group comprising a tunnel lining ring, shaft lining and the like, the coupler device comprising a double ended male first part having a substantially cylindrical portion adjacent to both ends, each substantially cylindrical portion having a surface which is formed into a series of grooves, a second part incorporating a reverse tapered sleeve for retention in one of the construction segments and a third part having an expandable collar formed of a plurality of arcuate segments, said arcuate segments having complementary grooves on their inner surface to mate with the cylindrical portion of said first part and a tapered external circumferential portion to abut the reverse tapered sleeve of said second part, said arcuate segments being retained elastically within the second part.
The arcuate segments maybe retained by a membrane of elastically flexible material.
In use, as two tunnel lining segments are urged together with the male part engaged in the recesses in both segments the cylindrical grooved portion adjacent to both ends of the device abuts the internally grooved arcuate segments retained in the sleeve at the base of the recesses cast in the segments, forcing back and radially outwards the expandable collar formed by the arcuate segments.
The movement of the expandable collar is resisted elastically which forces the mating grooves around the internal surfaces of the ring of arcuate segments to engage the cylindrical grooved portion of the male part of the device.
The tapered external surfaces of the ring of arcuate segments engage the surrounding reverse tapered sleeve thus locking the male part of the device into the recess formed in the sides of the segments preventing the device from pulling out.
When segments are urged together it is to be expected that the abutting faces of the tunnel rings do not fully contact one another. The relationship between the grooved cylindrical portion adjacent to both ends of the male part of device and the expandable collar formed by the arcuate segments is so arranged as to start the expandable collar engaging the grooved cylindrical portion of the male part of the device and the tapered external surfaces of the ring of arcuate segments engaging the surrounding reverse tapered sleeve prior to fully closing the gap between the adjacent segments.
When segments are urged together it is to be expected that the abutting faces of the tunnel rings do not initially fully align one to the other. The relationship between the expandable collar formed by the arcuate segments and the abutting surface of the surrounding reverse tapered sleeve is so arranged as to allow each arcuate segment of the expandable collar to individually engage the grooved cylindrical portion of the male part of the device prior to full alignment between the adjacent segments.
The significant advantage gained from this invention is that the restraint does not rely on geometric interference. The highly accurate dimensions of the recesses in the segments and the extremely tight tolerances required when forming the existing devices are not necessary. This means that the device is easier to use, easier to manufacture and more practical.
The segments may be made of concrete.
The central male portion of the device may be made of plastic or similar material to provide the necessary strength and durability.
The central male portion of the device may incorporate additional strengthening inserts of other material along its length.
The central male portion of the device may be double conical in shape to assist in aligning the tunnel segments.
The arcuate segments forming the expandable collar may be identical and formed from plastic or similar material to provide the necessary strength and durability.
The arcuate segments forming the expandable collar may be integral at their base with an elastic ring formed from plastic or similar material to provide the necessary strength and durability.
The expandable collar may be formed of any number of arcuate segments.
The expandable collar may be retained within an elastic membrane which may be formed from plastic or similar material to provide the necessary strength and durability.
The external surface of the central male portion of the device may be serrated or recessed.
The external surface of the cylindrical ends of the central male portion of the device may incorporate a series of grooves or recesses.
The grooves or recesses around the external surface of the cylindrical ends of the central male portion of the device may be individual concentric rings or threads or discrete recesses.
The grooves around the internal surface of the arcuate segments forming the expandable collar of the device may be individual concentric rings or threads or discrete recesses in order to mate with the grooves around the external surfaces of the central male portion of the device to maximising the locking forces between the central male portion and the expandable collar.
The external surface of the arcuate segments orming the expandable collar includes a reverse tapered portion to assist in locking the central male core into the recesses.
The external surface of the arcuate segments forming the expandable collar may have ridges or recesses to assist in maintaining its alignment with the external sleeve.
The internal surface of the external sleeve may have ridges or recesses to assist in maintaining the alignment of the arcuate segments forming the expandable collar.